Mixing machine



Feb. 5, 1952 1. M. E. AITKEN MIXING MACHINE Filed Sept. 4, 1947 f l l aI F/Gl.

Patented Feb. 5, 1952 UNITED PAT OFFICE IamMillen Ed lf iittit zljfieam,England-I Application September 4, mrnseriali No. 772,057

In Great'Britain September 9, 1946 The present invention relates tomachines for intimately mixing or blending ingredients efmix-f tures:together, particularly when in powderor'T comminu-ted form, to obtain a.thoroughly homogeneous product;

Hitherto mixing machines of this-kind have been of two main types. Inone type-themixing' takes place in a stationary vessel or hopper; inwhich is disposed a vane; paddle, or bladestructure which is rotatedabout a horizontal-101': vertical axis from: which the vanes; or thelike, project or radiate.- In the second type, the mixin is eifectedin avessel ordrum whioh is rotatable" about a horizontal axis; so that theingredients are tumbled as the vessel" rotates; To enhance the tumblingaction it is a common. practice to provide vanes 01" blades fixed. tothe interiorv of the vessel or drum, and further to improve; the mixingaction, looseobjects such aschains or balls are often placed'in thedrum.

The first type of machine has the disadvantage; of requiring a veryheavy starting; torquezwhen' the? vane; structure is not started,rotating before, the vesseli is fullycharged with: the; ingredients; in"consequence of which. it is often necessary? to set-the van e structurein motion-heforettheivessel is fully charged; Similarlyzifthe-vanerstructure is accidentally" stopped" or h'as to: be: stopped.for some special reasen, .befo1:e: the; mixing; operation is completed,it may become necessary-taunload some of the contents" of the" vesseibetorenthe vane'structure can-be started moving agaim to resume themix-ing operation; *F urthermorewith this type ofmixer there are lilielytote-unmixed pockets of the ingredients-which escape the stirring actionof the vanes orthe like, "due- 130 their lodgmenti-n recesses, suclrasdi'scharge: connec! tions; or' inother spaces which are not-swepbythevanes or blades;

r The main disadvantage of the second of mixer is that it is very slow"in action, in;- conse quence' of which a considerahie time" isxtaliem tosecure thorough admixture of the in-gredients, atthough the m-ixingaction i s very efficient.-

The objectof "thisinventiorr is t'o. provide an im Thdiuht or casing mayhave a smooth: interi'or; orit may have blades or vanes fixed. there.-to, and the driving mechanisms for the. drum and vane structure-may besuch-as to enablethem: to be rotated in the samedirecti'on or inopposite directions In order that the invention may be clearlyunderstood and readily carried into. practice it is illustrated, by way:of" example-only; by the. accoinpanyi-ng'v drawings, which:

Figure I is a sectional diagram offa mixer construeted' in accordancewith the. invention; and

Figure-Zisan end elevationthereof.

Referring to the drawings, the: mixing machin comprises; a mixing: drum.A. open. at! one end'but adapted to liezci'osed bya removable cover B.At its closed end" thedrum: A. has an axial hollow spigotshaft: Crunning in ballibiea-rings; D; mounted'i n acylindrical casing Wwhich'carries a frame structure comprising spaced platesG, supporting anelectric motor F? for: driving the drum A. The drive: is efiect'ed fromthe motor" F, through reduction gearing-incorporated in; the. motorcasing; and a drivingbeit passing over a pulley E mountedorr theholfowspigotishait C.

At right angles to: the; axis of the drum A the casing 'W carriestrunnions R which are supported by bearings in the fixedframeoithemachine (not shown). By rotation about the trunnions- R the A can be:disposed with its axis horizontaL'a-s in Figure. 1', in the; runningposition, or it canbe disposed with: its axis verti cal, either in itsfilling position. FE with itszend open-ingdirected upwardly, when it.canv be charged-0n removal of coverB, or in its emptying' position EPwith its end opening directed downwardly, when if its cover'B isremoved; its con-tents canhe-dischargedi In addition to means for"rotating" the mixing A as: described above, the machine alsoincorporates means-ior' rotating a mixing rotor: I-I within the'drum- A,when desired, at a. variable and controlled speed in the reversedirection. to thatof'the Themixing rotorH comprises-a spindle Isupporting a plurality of helical blades or vanes by means of'radialarms or spokes". The. spindl'eI is journal-led in suitable bearings atopposite endsiof the drum A and at the closed end of the; drum'extendsthrough the bearings, and. through the hollow spigot shaft C andpulley E; At its end the spindlfle-Iis solidly: coupled/co a spur; wheelL which formsthe centralpinion of a sun.-andplanet type ofepicyclicgear. The planet pinions Ivf'of the 1 epioycli'e gear: are mounted. onstub fixed in relation to the frame GG by a tubular arm, constituting abearing tube for a spindle V.

on which is mounted a bell crank lever Q. The

short arm of lever Q is anchored to the other end of the brake band P,so thatby' applying-pressure to the handle of the lever Q the brake bandP can be tightened about the rim of the carrier disc 0.

The method of operation of the apparatus is as.

follows:

The mixing drum A is rotated about trunnions R .until its axis isvertical and the drum is in its upper position FP. On removal of thecover B the ingredients to be mixed are loadedinto the drum A and thecover replaced. The drum A is then again rotated about trunnions B intoits horizontal running position and the motor F started, with the brakeband P released.

The mixing drum A will then rotate. and in doing so it will carry withit the vaned rotor H, due to the friction resulting from the presence ofthe ingredients to be mixed, the carrier disc 0 being free to rotate.After a few revolutions of drum A the mass of materials will be brokenup by the tumbling .action which takesplace.

The brake band P is then graduallytightened, by operating lever Q, aboutthe flange of carrier disc 0, bringing the vaned rotorH gradually torest, until finally it will commence to accelerate in the oppositedirection to drum A, to its maxi mum speed, attained when the carrierdisc 0 is held stationary by the brake band P. The actual relationshipbetween the final speeds of the drum A and rotor H will depend upon therela tive numbers of the teeth of the various wheels constituting theepicyclic gear.

On completion of the mixing'process the elec= tric motor F is stoppedand the mixing drum A is rotated about trunnions B into its downwardlydirected position EP with its axis vertical. cover B is then removed,and the contents of the drum discharged into a hopper or container. Ifnecessary the motor may be restarted, after removal of cover B, tofacilitate such, evacuation, either with, or without application of thebrake band P to cause rotation of the vaned rotor H during thedischarging process.

The initial mixing process in which the drum A and vane structure Hrotate together, without relative motion, will not throw any excessivestarting torque on the driving gear, since there will be little or noresistance to rotation of the whole mass in bulk. As soon as rotationstarts, the gravitational action on the ingredientsand the' action ofstatic friction will break up the mass of the ingredients by tumbling sothat a relative motion can be initiated as between the vane structureand drum, which can be gradually increased by slowing down or speedingup one or other of them, without unduly increasing the 3 driving torque.

It will be appreciated that the tumbling action which occurs willeffectively prevent the formation of unmixed pockets of ingredients,whilst the application of relative rotation to the drum and The vanestructure will ensure efficient and rapid mixture of the ingredients.

An important use for the improved mixer according to the invention isfor the admixture of dye powders, in the nominally dry state, since itis of the highest importance for dye powders to be thoroughly wellmixed. This would normally call for the use or an ordinary drum mixerwith its consequent long mixing period, whereas the improved mixeraccording to this invention has the advantage of the drum type of mixercou- 4 pled with the speed of action of the rotary vane type of mixer.

It shall be clearly understood that the invention is in no way limitedto the details of the construction of machine described and illus--trated, and furthermore that various other constructions of machineembodying individually and/or relative rotatable mixing drum and vanedrotor may be devised, without departing from the scope of the invention.4

1. A mixing machine including a support having a substantiallyhorizontal bearing; a-horizontal drum with a closed end and an axialspindle disposed within the drum and projecting rotatably out throughthe closed end of said drum and rotatably through the bearing from oneside of said bearing; a vaned rotor formed on the spindle Within saiddrum; a hollow shaft connected to the drum and rotatably mounted in saidbearing and rotatably supporting said spindle externally of one end ofsaid drum; drive means for driving the hollow shaft; transmission meansconnected to said spindle, drive means and hollow shafton the outer endsof the spindle and hollow shaft; and manually operated control meansdisposed exteriorly of the side of said bearing and exteriorly of saidtransmission means effective to selectively cause the drive means torotate the drum and rotor positively in the same or opposite directions.

2. A mixing machine including a support having a' substantiallyhorizontal bearing; a horizontal drum with a closed end and an axialspindle disposed within the. drum and projecting rotatably out throughthe closed end of said drum and rotatably through the hearing from oneside of said bearing; a vaned rotor formed on the spindle within saiddrum; a hollow shaft connected'to one end of said drum and rotatablymounted in said bearing and rotatably supporting said spindle externallyof one end of said drum; drive means for driving the hollow shaft;transmission means connected to said spindle, drive means and hollowshaft on the outer ends of the spindle-and hollow shaft; manuallyoperated control means disposed exteriorlyof the other side of saidbearing and exteriorly of said transmissionmeans effective toselectively cause the drive means to rotate the drum and rotorpositively in the same or opposite directions; 'and means for raisingsaid drum, hollow shaft and spindle about a horizontal axis transverselydisposed with respect to the axis of said spindle into a substantiallyupright position for said drum.

3. A mixing machine comprising a cylindrical drum mounted upon an axialspindle projecting from one end ofsaid drum; -a first cylindrical sleevesurrounding the projecting part of said spindle and fixed to the end ofsaid drum, a second cylindrical sleeve surrounding and rotatablysupportingthe first sleeve; aligned supporting trunnions projecting fromsaid second sleeve at right angles to the spindle axis; a supportingstructure also extending from said second sleeve at right angles to boththe trunnion axis and the spindle axis; a driving motor carried by saidsupporting structure and operative to drive said first sleeve and drumcontinuously at invariable speed; and controllable transmission meansfor driving said spindle from said motor at a variable speed andineither direction in relation to the direction of rotation of said drum.

4. A mixing machine comprising a cylindrical drum mounted upon an axialspindle projecting from one end of said drum, a first cylindrical sleevesurrounding the projecting part of said spindle and fixed to the end ofsaid drum; a second sleeve surrounding and rotatably supporting thefirst sleeve; alined supporting trunnions projecting from said secondsleeve at right angles to the spindle axis; a supportingstructure alsoextending from said second sleeve at right angles to both the trunnionaxis and the spindle axis; a driving motor carried by said supportingstructure, and operative to drive said first sleeve and drumcontinuously at invariable speed, a driving pulley mounted on said firstsleeve; a brake drum mounted on said spindle adjacent to said drivingpulley, flanges on the opposed sides of said pulley and brake drumadapted to form therewith a cylindrical chamber; internal teeth disposedwithin said flanges, a sun pinion on said spindle; axis pins mounted insaid chamber on the side of said brake drums; and planet pinionsrotatable on the latter axis pins and meshing both with said sun pinionand also with the internal teeth of both of said flanges on the drivingpulley and brake drum; and a manually operated brake device operative onsaid brake drum to control its speed of rotation between a predeterminedmaximum speed and a stationary condition.

5. A mixing machine comprising a cylindrical drum having an axialspindle extending there through and projecting from one end of saiddrum; an elongated sleeve surrounding the projecting portion of saidspindle and fixed to said one end of saiddrum; bearing means surroundingand rotatably supporting the elongated sleeve; two aligned supportingtrunnions projecting externally in opposite directions from said bearingmeans at right angles to the spindle axis; a supporting structure alsoprojecting rigidly from said bearing means substantially at right anglesto both the trunnion axis and said spindle axis; a driving motor mountedon said supporting structure and operative to drive said elongatedsleeve and drum continuously at a predetermined speed of rotation; andcontrollable transmission means for driving said spindle at variablespeed independently of the speed of rotation of said drum.

IAN MILLER EDINGTON AITKEN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 102,591 Randall May 3, 1870600,168 Penn et al. Mar. 8, 1898 749,286 Gerner Jan. 12, 1904 1,234,230Sturtevant July 24, 1917 1,504,832 Pouget Aug. 12, 1924 1,750,558Zettergren Mar. 11, 1930 1,859,690 Aeschbach May 24, 1932 1,880,731Oileau Oct. 4, 1932 2,059,485 Payne et al Nov. 3, 1936 FOREIGN PATENTSNumber Country Date 208,360 Germany Mar. 24, 1909 379,823 France Nov.20, 1907 381,244 France Dec. 31, 1907

